Archive for the ‘Epidemiology’ Category

An unusual hazy weather condition in parts of the country have been giving people serious cause for concern, but a senior official of the Nigerian Meteorological Agency [NIMET] says there is no need to press the panic button just yet, describing the situation as part of a change in the climate around the world.

For days now, the weather in most parts of the country has been hazy reducing visibility drastically and even disrupting flight operations in some cases.

Several passengers have been affected as flights at airports in Lagos and the northern states have either been cancelled or rescheduled to the poor weather condition.

An official of Aero Contractors who did not want his name in print said bad weather led to flight cancellations, a situation which also affected other airlines.

Chanchangi Airline Spokesman, Ibrahim Adamu, explained that foggy weather had affected the airline’s flights to Kaduna and Abuja on Friday but flights were operated on Saturday and Sunday.

He said flights were cancelled or rescheduled for safety reasons, and urged passengers to bear with the airline as the decision taken was for their own good. Hazy weather reduces visibility and makes it impossible for pilots to land or take off.

The Nigerian Civil Aviation Authority, the NCAA has alerted airlines on the adverse weather conditions and has asked all airline operators and pilots to adhere strictly to aviation directives in order to ensure safety in the airspace.

The NCAA says it is monitoring the situation closely with the Nigerian Meteorological Agency, but that passengers should expect flight cancellations.

Meanwhile, series of text messages have been spreading in the country over the changing weather, thereby giving growing concern over the climate change in the country.

One of these disturbing text messages which reads “Be careful from 20-28th of March, there is possibility of an ACIDIC RAIN. It rains normally but it may cause skin cancer it you expose yourself to it. So ALERT your dear ones. This information is from NASA in USA. DO Not Neglect. Please forward this to your friends, better be cautious than sorry”, has created fear and raised questions among people in the country due to the current haze and weather change.

The Deputy General Manager, directorate of weather forecasting services, Nigerian Meteorological Agency [NIMET], Mr Sampson Wilson has refuted the negative reports saying there is no cause for alarm. The haze in some parts of the country is just part of the climate change which has affected many countries all over the world.

It could be recalled that NIMET recently reported a foggy atmosphere which has led to deteriorating horizontal visibility across Nigeria, attributed to the dust haze emanating from the Sahara desert.

NIMET also alluded to the presence of a significant build up of surface pressure in the Sahara and Sahel region.
This resulted in the lifting of considerable quantity of dust particles into the atmosphere, transported southwards, causing reduction in horizontal visibility in the North North zone.

Cities where horizontal visibility has reduced to less than 800 metres include Maiduguri, Potiskum, Nguru, and Kano.
NIMET said it is “closely monitoring and keeping track of the current episode of the transportation of dust particles from the source regions into the country and the likely effects of the dust haze phenomenon.”

It added that further southward transportation of the dust particles will be slow, due to the prevailing light winds, while the dust particles are expected to stagnate over the affected areas as they slowly spread westwards and southwards to places such as Yola, Gombe, Bauchi, Jos, Kaduna, and Sokoto.

Other cities such as Abuja, Makurdi, Minna, and Ilorin in the North Central are expected to experience a slight increase in the concentration of dust particles, but with a mild effect on horizontal visibility.

The South will only experience a slight reduction in humidity due to the southward extension of the influence of the current dust haze, according to the NIMET.

Last Monday, over 90 percent of all the flights at the nation’s airports were cancelled or delayed. There was a thick fog in the atmosphere. The visibility was poor. It was less than 500 metres and this posed danger for aircraft all over the region.

In a particular instance, a passenger aircraft that was to land in Nigeria’s airport ended up in Cotonou, Benin republic because of poor visibility, according to airport sources.

Haze in Nigeria (AP Photo/Sunday Alamba)

This reporter on his way to climate change engagements in Abuja was stuck at the airport.It was similar to an incident at Schipol Airport, Amsterdam on the way to India for a United Nations Climate Change conference sometime ago. Ironically, many climate change experts going for Climate conferences are being trapped the world over by erratic weather patterns. Incidences of meningitis have been on the increase in Nigeria for the past one-year as a result of excessive heat. This year has been unbearably hot in Nigeria and other countries in Sub Saharan Africa. In Nigeria the eleven frontline states in the north that have suffered from desert encroachment have been suffering from heat related ailments.

Early last year investigations revealed that over 200 people were killed by meningitis in Nigeria and Niger Republic in one week. There were outbreaks in 76 areas. There were 25,000 suspected cases and 1, 500 deaths in the first quarter of 2009. Although meningitis is a disease caused by an infection of the meanings, which is the thin lining that surrounds the brain and the spinal chord, experts have found a correlation between the weather and this disease. It is generally known that the disease attacks more people during the dry season because of dust, wind and cold nights. There were indications in the past one month that many people were treated for acute pneumonia in some hospitals as a result of the erratic and unpredictable weather which has also confused farmers about planting seasons raising fear about food production and security.

Apart from the reign of diseases as a result of harsh weather conditions in Northern Nigeria agriculture has been affected as a result of erratic weather patterns. The dryness has led to dry waterbeds and movement of people and their pasture to the southern regions thus causing tension and conflicts between the original inhabitants and the new comers. Experts at the United Nations and other global bodies have found over the years that the world’s climate has changed.

In one of his treatise on Climate Change in Nigeria and Niger, Professor Emmanuel Oladipo, a United Nations Development Programme (UNDP) Consultant and Nigeria/Niger Project, Niamey, confirmed that Climate change is a serious threat to efforts at poverty eradication, and sustainable development in Nigeria and Niger because the countries have large rural population directly depending on climate sensitive economic and development sectors (agriculture and fisheries).

Even in the southern states, medical experts hinted last week that cases of Tuberculosis have been on the increase.

Dr. Nath Ayo Macualay Medical Director, Macaulay Medical centre, Mushin, Lagos told The Guardian that apart from heat rashes that had been noticed amongst the populace within the period of intense heat, there has been an upsurge in Tuberculosis (TB) in the past one month.

Macaulay said that those who are at risk are those who were not immunized against TB. The Medical doctor said that when a tuberculosis patient spits on the ground, the TB virus can hang in the air for 42 days unlike other viruses such as gonorrhea that can die within one hour.

“If you breathe in the tuberculosis virus in the air through dust it very hazardous,” said Macaulay, adding that the “TB can be in the air because of a lot of dust”

Last Friday, the Federal government raised an alarm that tuberculosis is on the increase and that about one million Nigerians are afflicted by the disease.

Haze in Lagos (Photo: Femi Adebesin-Kuti)

Dr. Victor Fodeke, the Head/Designated National Authority (DNA) Special Climate Change Unit, Federal Ministry of Environment, Abuja told The Guardian in Abuja last week that the sudden change in weather at this time of the year is a very serious problem.

According to him, this is the beginning of the worst thing to expect adding that this is evidence that greenhouse gases have altered the weather patterns of the world and Nigeria in particular. Dr. Victor Nkom, climate change expert/consultant to the Federal Ministry of Environment warned in Abuja that the dusty and hazy weather would trigger certain ailments amongst the populace who were not ready for the unusual weather.

Nkom said the dust in the atmosphere would trigger droplet infection because the dust will become the medium of propagating the various viruses and bacteria that are airborne.

Fodeke regretted that policy makers all over the world have underestimated the problem of climate change. He noted that a document written by Professor Charles H. Greene, of Cornell University’s Department of Earth and Atmospheric Sciences entitled: “A Very Inconvenient Truth,” published in the peer-reviewed journal Oceanography this month concluded that the United Nation’s Intergovernmental Panel on Climate Change (IPCC) 2007 4th “assessment report underestimates the potential dangerous effects that man-made climate change will have on society.” Adding that “even if all man-made green house gas emission were stopped tomorrow and carbon-dioxide levels stabilized at today’s concentration, by the end of this century the global average temperature would increase by about 4.3 degrees Fahrenheit, or about 2.4 degrees centigrade above pre-industrial levels, which is significantly above the level which scientists and policymakers agree is a threshold for dangerous climate change.” In the document, Professor Green and other co authors D. James Baker of the William J. Clinton Foundation and Daniel H. Miller of the Roda Group, Berkeley, California, USA are of the opinion that “reducing greenhouse gas emissions alone is unlikely to mitigate the risks of dangerous climate change” adding that society should significantly expand research into geo-engineering solutions that remove and sequester greenhouse gases already in the atmosphere. He concluded by adding that geo-engineering solutions must be in addition to, not replace, dramatic emission reductions if society is to avoid the most dangerous impacts from climate change.”

Tunde Akingbade writes for the Guardian Newspapers in Nigeria. This report was culled from The Guardian (30-03-10)

There are certain infectious diseases that are said to be climate sensitive. These diseases are described thus because of the observed change in their epidemiology following the probable effects of anthropogenic global warming.

Source: National Science Foundation, USA.

Some of these diseases represent the common face of the human-vector interaction as mediated by man’s environment. They also represent a huge health and economic burden to affected populations. It is thus important, in instituting control measures to combat the spread of these diseases, that there be a functional understanding of the various environmental parameters that influence the biology of these vectors and the natural history of the diseases that they transmit. Other non vector-related occurences such as heat waves, with attendant adverse health effects, also need to be studied and predicted.

The role of space technologies is very important in monitoring and understanding the influence of environmental parameters on vector biology and disease transmission cycles. Typically, earth observation systems that routinely monitor the environment give very useful data that can be adapted for the study of vectors, their associated diseases and other climate sensitive diseases. These systems operate with sensors located in water bodies, on the earth’s surface, above the earth’s surface, in the atmosphere and in outer space. These all combine to give a continuous stream of data to inform the scientific study of the climate and how its patterns are influencing the spread of diseases. This studies involve the complex task of disease modeling to aid public health interventions in curbing the spread and effect of such diseases. Interventions include chemical, physical, biological and pharmacological measures such as vaccinations, the distribution of Insecticide Treated Nets (ITNs), use of repellants, drainage of stagnant water, etc.

The advantages of space-based imagery for these studies include its reliable supply of data on a range of environmental parameters such as precipitation, temperature, Vegetation Indices, topography, etc. It makes these data available at varying temporal, spatial and spectral resolutions. Satellite data can be acquired at reasonable costs and much of what is freely available is being put to good scientific use already. To improve access to this, it is important that African countries invest in developing technical and scientific capacity to put them at the helm of disease studies affecting their environment and populations.

The plight of African farming and the need to develop adaptive systems to cope with the changes that may be forced on African populations due to environmental change has been touched on in an earlier post. The role that early warning systems can play in shaping this adaptive response has also been discussed in another post. This post has as its focus an examination of the interactions, as often abound in nature, between factors in the African environment, and how these interactions could contribute to the challenges being faced with precipitation, drought and food security. The role of space science and technology in arming researchers, scientists and government policy makers with the right information and predictive tools to evolve appropriate and evidence-based responses to these challenges is highlighted.

The flow of dust on the African continent is abundant. It has some of the world’s largest sandy deserts- the Sahara (the world’s largest hot desert), the Kalahari and the Namib. The Arabian desert extending from Egypt to Iran is also close by. These supply a stream of dust propelled by the trade winds and which blow huge amounts of dust over the continent towards the equator and the oceans. The effect of these dusty winds on rainfall is by acting as aerosols and interfering with the coalescing of water droplets in rain clouds. This leads to a dispersion effect on the water droplets, preventing rain drop formation and hence precipitation. The scourge of reducing annual rainfall on many parts of the African continent is as shown in the picture below. The socio-economic impact of this is better avoided. Food and water shortages in Kenya this year left about a third of the population in need of aid.

Another effect of dust clouds is on Sea Surface Temperature (SST) and its ensuing effect on tropical storms. Although not a major problem for the continent on its Atlantic end, the propagation of El Niño-La Niña events has been linked to droughts, tropical rainfall, storms, floods, malaria and even cholera incidence in some parts of Africa. The El Niño Southern Oscillation (ENSO) also bears links to other diseases. Space technologies play a crucial part in defining and predicting the occurence of these events and may also aid the mitigation process.

Amongst other uses of space technologies in keeping track of these environmental variables, their use in monitoring groundwater has also been demonstrated. Using results from the Gravity Recovery and Climate Experiment (GRACE) a joint NASA and DLR mission, a team of NASA researchers demonstrated receeding groundwater stores in India, most likely due to irrigation that has relied on these groundwater sources. Thus using satellite technology it is now possible to generate a comprehensive monitoring system that keeps track of not only the environmental variables affecting precipitation and drought, but also the effectiveness and effect of countermeasures developed as part of the anti-drought response.

Images from the Moderate Resolution Imaging Spectroradiometer (MODIS) on board the NASA Terra and Aqua satellites have been very useful in tracking the spread of dust on and away from the African continent. This has also helped in guiding researchers and scientists in observing the links between this spreading dust and various climatic and biological phenomena.

The image above depicts the flow of dust off the west coast of Africa. The following description from the NASA Earth Observatory states that,

“The Sahara experiences extreme variations in land surface temperature—from freezing temperatures at night to more than 54.4°C (130°F) during the day. The extreme daytime heating in the Sahara Desert, especially during the summer, causes instability in the lowest level of the atmosphere. Dust-laden air rises and begins moving westward. As the air travels—a trip that often takes several days—it continues heating. When this Saharan Air Layer moves off the African coast and over the Atlantic Ocean, it is undercut by a cooler, wetter layer of air. Air normally cools with altitude, but the Saharan Air Layer passing over cooler air currents causes a temperature inversion, which suppresses mixing. As a result, Saharan dust often travels across the Atlantic, sometimes remaining visible throughout the trip.”

Dust moves freely across the continent and blows off the coast driven by the various winds and thus goes to contribute to the soil profile of other parts of the world. It also settles in the ocean along its way adding nutrients and thus embellishing oceanic ecological patterns.

But what effect does this have on human health and livelihood? In looking at that we would like to consider the amount of the earth’s surface that is potentially exposed to airborne dust. Airborne dust has been described, by the National Institute of Health (NIH) in the United States, as the primary source of allergic stress worldwide. Deserts (in this case referring to non-polar arid zones) are major sources of dust particles.

D. W. Griffin has worked on using satellites to monitor the global spread of dust and linking this with its effects on ecology and human health. His work (in this paper with C. A. Kellogg) identified these effects on life forms, both human and in the oceans, and on various continents. The identified effects include coral bleaching, algal blooms and allergenic effects on humans, including aggravating asthma. This may not be solely due to desert dust but the increased concentration of these dust particles, some as fine as 2.5 microns, in combination with other industrial and environmental pollutants may play a role in immunogenic responses that cause ill health. The human respiratory mucosa usually traps dust particles and tries to clear the respiratory passageways of these irritants. However, these very fine particles may exacerbate that response. This is of more serious concern in individuals with compromised respiratory and immunologic responses.

A lot of the research in this area has focused on the Trans-Atlantic effects of dust spread. This has had effects in the USA and the Carribeans. Griffin reported studies stating a 17 fold increase in paediatric asthma between 1976 and 1999. Other studies identified a relationship between dust events and hospital asthma visits. This however was not solely due to dust of African origin, which was said to have contributed (~50%) alongside other sources of dust activity. Also, the link between dust events and the epidemic prone disease, meninigitis, is already being investigated.

In strengthening the capacity to detect which dust events and sources are responsible for some disease events in Africa, the use of satellite technologies play a very important role. This occupies a relevant area of research alongside other initiatives to boost the monitoring and reporting capacity for Air Quality Indices. There are various aspects of using available resources for strengthening our awareness of the effects of inspired air on human health. The training of scientists and continued collaboration with the environmental sector, meteorologists, climatologists, public health researchers, and healthcare policy makers is a definite step towards developing a functional warning system with strong interventional capability. Academic research institutions can mobilize resources to develop training programmes in support of this crucial area of need. Ultimately such efforts may not go far without governmental support. The role of environmental and healthcare organizations in developing awareness and response capacity and acting to engage political leadership is also of importance. Hand in hand, individuals and associations can work to bring about a safer and securer environment to live and work in.

You can follow the progression of the Saharan Air Layer (SAL) on this site with frequently uploaded satellite images.